The Austrian carded 10 birdies in a nine-under par 63 to reach 17-under at the Kuala Lumpur Golf & Country Club, although even that was not enough for round of the day.
Wiesberger started as he meant to go on, with birdies at the first five holes, and he made it to the turn in 31 despite dropping a shot at the eighth.
But that would prove to be his only bogey of the day and after stalling a little from the 11th, he birdied the last three holes to complete a superb round.
Halfway leaders Alejandro Canizares and Lee Westwood remain in touch for a final day title bid, but neither could match the scoring Wiesberger was putting up.
Canizares is his closest challenger on 15-under, but even a reasonable 68 paled in comparison with the new leader – the Spaniard had six birdies and an eagle but four bogeys, including one at the last, proved costly.
Westwood struggled on Saturday, and for a while looked like dropping some way off the pace, but his third and fourth birdies of the day at 17 and 18 at least moved him up to 14-under, a tie for third alongside Paul Waring.
Waring managed a couple of eagles in his 65, and he also finished with three birdies to improve his hopes of a first European Tour victory.
The biggest move of the day came from India’s Anirban Lahiri, who put up a new course record with a 10-birdie round of 62.
Lahiri birdied five of his first six holes and went to the turn in 30, picking up four more shots on the way home to move up from 16th to fifth, five shots behind Wiesberger.
But it proved to be another disappointing day for one of the pre-tournament favourites, Graeme McDowell, who finds himself 12 off the pace after struggling round in level-par 72.
McDowell was in good position after Thursday’s opening round, but a 73-72 run leaves him with an uphill battle even to finish in the top-10.